This application is related to the packing industry and, more specifically, to loading and unloading containers.
The produce industry provides a ready example of the need for efficient methods and devices directed to the unloading of containers. For example, in the produce industry, produce is gathered using various techniques, then sorted, prepared, and packed for ultimate shipping to downstream wholesale and retail markets. Gathered produce, however, generally varies with each item of produce as to its size, shape, and quality. This variability affects how produce is sorted, graded, prepared and packed. It is also a factor in other industries involving package handling generally. Various systems have been developed over the years with the intent to more efficiently handle the grading, sorting, preparing, and packaging of produce and other items. Nonetheless, handling and packaging produce and other items remains extremely labor intensive, in the sense that manual labor is a primary factor of production input in all handling and packaging efforts. This factor gives rise to many problems associated with unloading or loading containers. For example, manual labor is frequently contracted-for on a short-term basis and often subject to frequent interruptions in the supply of labor thereby adversely affecting the scheduling of loading and unloading containers and related labor schedules.
The ability of managers to monitor and maintain the level of care exerted by manual laborers in carrying out container loading and unloading along with related packaging chores affects both the rate and quality of packing output. The resulting variability and uncertainty related to labor supply, packing speed, and packing quality add to the overall administrative costs of package handling operations. Other package handling systems directly addressing some of the problems have also developed over the years, especially relating to xe2x80x9ccontainerization.xe2x80x9d Forklifts and other machinery useful for loading and unloading also have facilitated bulk packing and transportation using such containers.
Nonetheless, there are limits to the efficiencies created using containerization and existing machinery, especially in produce handling where numerous small objects must be loaded into containers often at a remote field site and then unloaded en mass at a central processing point. Produce, aside from comprising numerous small articles, must be sorted according to relatively small variations in size. Of particular importance is the avoidance of unnecessary or rough transfer movements in the loading and, especially, the unloading process. Conventional container unloading systems exhibit many problems in this respect. Existing systems that attempt to mechanize what would otherwise be done by manual labor thus nonetheless give rise to risks of roughly mishandling produce or other container product.
Some newer methods provide smoother mechanical movements. For example an earlier patent of the Applicant (Herrin, U.S. Pat. No. 5,797,716) describes an apparatus and methods for xe2x80x9ckiss contactxe2x80x9d product handling. These methods, however, do not completely smooth pivotal rotational movements, and moreover achieve smoother discharge and return movements utilizing a single-centered boom arm for providing container lift. Containers being unloaded must inevitably be pivoted along an axis of rotation roughly perpendicular to the plane of pivot for discharging the container contents, concentrating stress on the boom arm and the pivot axis. (See Applicant""s earlier patent, Herrin U.S. Pat. No. 5,797,716). If the container does not rotate efficiently through the pivot plane, the energy and machinery costs of driving such a mechanism will be correspondingly higher, especially in terms of wear and tear on the associated mechanical elements of the system. Thus, from both a marketing and operations control perspective, unsmooth movement and undistributed stress in discharging the contents of container, inevitably lead to bruised produce and stress and put costly strains on container handling equipment.
With the foregoing in mind, it is an object of the present invention to provide a container contents unloading apparatus and method that effects a smooth operational discharge and return of an open-ended container and return of the emptied container, specifically by providing a more fluid, smoother movement through the pivot plane as the container is pivoted to discharge the contents followed by a smooth return of the emptied container for repeating the process.
It is a related, though additional objective, to produce rotational pivot movement that distributes the load stress on the lift elements and the pivot axis, thereby achieving not only smoother, more fluid pivotal rotational movement but doing so in a manner that reduces wear and tear on the associated lift elements. Thus, it is also an object of the present invention to provide a container contents unloading apparatus and method that eliminates the stress placed on boom arms and mechanical elements found in more conventional systems by replacing those elements with an alternative pivoting mechanism.
It further is an object of the present invention to provide a container contents unloading apparatus and method that facilitates the efficient maintenance and replacement of parts of a container contents unloading system. With respect to this object of the present invention, specific mechanisms are employed to utilize less expensive and more easily replaced components.
It is still another object of the present invention to more efficiently control the discharge of a container to effect a more steady and stable transfer from the container to a receiving device of the container contents, thereby providing a more manageable flow of the amount of produce being transferred onto, for example, a produce conveyor when a container having produce is emptied onto the produce conveyor.
It is a still further object of the present invention to provide greater speed to the pivoting movement for discharging container content and returning the emptied container without adversely affecting the smoothness of the pivotal lift or return-to-position movements. Achieving this objective thus allows for rapid and efficient container handling while relieving stress on the systems mechanical elements and reducing the risk of improper handling of produce that would bruise or otherwise adversely affect the quality of the discharged container content.
More particularly, a container contents unloading apparatus and methods for discharging a filled container more smoothly and fluidly thereby enhancing overall handling efficiency in unloading of container contents is provided according to the present invention. The apparatus preferably includes a container conveyor positioned to convey a plurality of filled open-ended containers. A container carriage is positioned within a frame overlying the container conveyor for slidably receiving filled containers as they are conveyed along the container conveyor. An upper portion of an end (i.e., the proximal end) of the carriage is pivotally connected to the frame to create a pivot axis. Pivoting movement is effected by a lifting of the other end (i.e., the distal end) of the carriage thereby causing the carriage to pivot at the proximal end about the pivot axis as the distal end is lifted. Specifically, the lower portion of the distal end of the carriage is lifted upward once the carriage has slidably received a filled open-ended container. The open-ended carriage-held container thereby pivots, and the product contained therein is discharged through the container""s open end. The carriage then returns to an originating position and releases the emptied container.
The upward lift is caused by movement of at least two endless loops (e.g., belts or chains) that rotate in closed paths about rollers connected to the frame. Each loop is preferably connected to a link that is connected to the carriage. Thus, driving the loops propels the link connecting the loops and the carriage, resulting in the upward lift and pivot of the carriage.
Preferably, rollers support each loop and are aligned so that each loop has two distinct center lines, one extending upward from the distal end of the closed path to an intermediate point and the other extending downward from the intermediate point to the proximal end of the closed path. This belt and roller arrangement causes the link to move in a manner that smooths the upward lift and fluidly returns the container carriage to its initial position for releasing the emptied container and receiving for discharging another filled container. Specifically, the distal end of the link moves along the identical closed path of the loops, first upwardly from distal to intermediate point, then downwardly from intermediate to distal point, then upwardly from distal to intermediate point, and finally, completing the closed path, moving downwardly from intermediate to distal end point. The movement of the link propels the lower portion of the distal end of the carriage to sweep through the pivot plane about the pivot axis.
This smoother, more fluid movement, as pointed out above, provides a correspondingly smoother discharge of the container contents as well as a smoother, more fluid return of the emptied container. Moreover, by smoothing the movement of the link, the present invention reduces wear and tear on the system, especially as compared, for example, to systems using a rotatable boom arm. Replacing a boom arm with a combination loop (e.g., endless belt or chain) and rollers provides additional advantages alluded to above in regard to maintenance of the system: that is, the loop and roller arrangement is structurally simpler and facilitates replacement of individual discrete pieces (i.e., the belt and/or any subset of rollers). Thus the advantages of the present invention are multifold, including effecting smoother rotational pivot in a plane for discharging the contents of container and returning the container to an originating position, distributing the load stress in lifting, and facilitating easy maintenance of the system.